On audio amplifiers, errors or faults may occur at times on the connections between the amplifier outputs and the load (loudspeakers). For example, the output may be grounded or connected to the supply line for want of insulation of the cable supplying the signal to the load; the load may be disconnected due to an interruption on the signal supply cable; or metal fragments on the printed circuit on which the connections are made may result in short-circuiting of the outputs or at points of different potential.